KittenTTS Flutter

On-device text-to-speech for Flutter.
Generate speech on Android, iOS, macOS, Linux, and Windows without sending text to a cloud TTS API.

Developer preview. APIs may change between releases.

Playback is intentionally app-provided. Pass an AudioPlayer implementation to KittenTTS.create() when you want speak() or play().

See It In Action

iOS · Basic example     Android · Basic example     Web · Browser example

What Is KittenTTS Flutter?

KittenTTS Flutter lets you add local speech synthesis to a Flutter app:

• Text-to-speech - neural voice synthesis from plain text.
• On-device inference - powered by KittenTTS and ONNX Runtime.
• Private by default - no cloud TTS request after assets are available.
• Offline-ready - download once into the app cache, or point the SDK at local model files.
• App-friendly output - play audio directly, save WAV data, or use generated word timings for read-aloud UI.

No cloud. No API key. No text leaving the device for speech generation.

---

The SDK sends anonymous generation analytics; see Getting started for details and opt-out.

SDK

Runtime	Status	Docs
Flutter Android	Developer preview	Getting started
Flutter iOS	Developer preview	Getting started
Flutter macOS	Developer preview	Getting started
Flutter Linux	Developer preview	Getting started
Flutter Windows	Developer preview	Getting started

Install:

flutter pub add kittentts_flutter

---

Quick Start

Install the SDK:

flutter pub add kittentts_flutter

Generate audio in memory:

import 'package:kittentts_flutter/kittentts_flutter.dart';

final tts = await KittenTTS.create(
  onProgress: (progress, info) {
    print('setup ${(progress * 100).round()}%');
  },
);

final result = await tts.generate('Hello from KittenTTS on Flutter.');

print(result.duration);
print(result.wavBase64());

await tts.dispose();

Play audio through your app's audio layer:

final tts = await KittenTTS.create(player: myAudioPlayer);

await tts.speak('This voice is generated on the device.');

Implement AudioPlayer with the package your app already uses, such as audioplayers, just_audio, or a native audio bridge.

Full getting started guide →

---

Sample Apps

• examples/basic - basic model, voice, speed, Generate, Speak, and Queue demo controls.
• examples/word_timings - word highlighting with generated timings.

---

Features

• On-device TTS inference on Android, iOS, macOS, Linux, and Windows.
• Model download and cache with progress callbacks.
• Local/offline model files for apps that cannot depend on a first-run download.
• CE phonemizer through Dart FFI on native platforms.
• Playback interface for app-provided audio players.
• FIFO playback queue for serializing generated clips.
• WAV output as raw PCM samples, bytes, or base64.
• MP3 helpers are not bundled until a small non-GPL Flutter encoder is available.
• Word timings for read-aloud highlighting.
• Streaming generation for longer text.

---

Supported Models

Start with nano-int8 for the smallest download. Use larger models when quality matters more than size.

Model	ID	Parameters	Approx download	Use case
Nano int8	"nano-int8"	15M	25 MB	Smallest app/download size
Nano fp32	"nano"	15M	56 MB	Nano quality without quantization
Micro	"micro"	40M	41 MB	Better quality, still compact
Mini	"mini"	80M	80 MB	Highest quality option

Models and voices →

Voices

Bella, Jasper, Luna, Bruno, Rosie, Hugo, Kiki, Leo

await tts.speak('Luna speaking.', voice: 'luna');
await tts.speak('Slower Bruno speaking.', voice: 'bruno', speed: 0.85);

---

Docs

• Docs overview
• Getting started
• Playback
• Local/offline assets
• Word timings
• Models and voices
• API reference
• Troubleshooting

Tutorials:

• Tutorials are not written yet for the Flutter SDK.

---

System Requirements

• Flutter >= 3.22

• Dart >= 3.4

• iOS 16+

• macOS 14+

• Android API 21+

• Linux and Windows native build toolchains for desktop targets Runtime dependencies installed by the SDK:

• flutter_onnxruntime

• path_provider

• http

• archive

• ffi

Audio playback is optional. Use an app-side audio package such as audioplayers, just_audio, or your own native audio layer.

---

Roadmap

• Add first-party playback adapters for common Flutter audio packages.
• Add more streaming playback examples.
• Add more reader-app helpers around pause, resume, and seek state.
• Support future KittenTTS model releases as they become available.

Need something specific? Open an issue.

---

Community And Support

• Website: kittenml.com
• Repository: KittenML/KittenTTS-flutter
• Discord: Join the community
• Demo: Hugging Face Spaces
• Issues: GitHub Issues

Commercial Support

Commercial support is available for teams integrating KittenTTS into their products, including integration assistance, custom voice development, and enterprise licensing.

Contact us or email info@stellonlabs.com to discuss your requirements.

License

Apache 2.0. See LICENSE.

Disclaimers

KittenTTS Flutter is a developer preview and APIs may change between releases. Generated speech quality, pronunciation, timing metadata, and playback behavior can vary by model, platform, device, and audio backend. Review generated audio before using it in production workflows.

The SDK runs speech generation locally after assets are available. Anonymous generation analytics are enabled by default and can be disabled with analytics: false.